There were some interesting musical choices. I was pleased that Signature went for the full score, including the second half of "The Contest," all of "Parlour Songs," and (particularly unusual) Judge Turpin's rendition of "Johanna." I was less pleased with some of the orchestration. Particularly, the woodwinds in the quartet version of "Kiss Me" did not work for me, though I'm not sure I can articulate why.
As for the performances, I enjoyed them for the most part. I thought Sherri L. Edelein's comic timing as Mrs. Lovett was superb. Chris Sizemore (as the Beadle) and especially Sam Ludwig as Tobias have exceptional voices. I have some reservations about Erin Driscoll as Johanna, as she sounded a bit shrill at a few points.
I've always been impressed with Sondheim's ability to make the darkest material sympathetic and this production shows that off well. Assuming you can handle the gore, it's well worth seeing.